Rep. Adam Schiff (D-Calif.), the top Democrat on the House Intelligence Committee, responded to President Trump’s accusation that the Obama administration investigated his campaign in an effort to help his opponent Hillary Clinton, saying in a tweet Monday that Trump’s own failure to act on Russian election interference is a “dereliction of duty.”

“The FBI investigation began when it was discovered that the Russians had secret discussions with your foreign policy advisor about dissemination of stolen Clinton emails,” Schiff tweeted.

Schiff also criticized Trump for claiming that former President Obama “did nothing” about the Russian election interference, asking Trump how he can “criticize Obama for not doing more, when you do absolutely nothing?”

“This is dereliction of duty,” he added, referring to a New York Times report that the State Department had not spent any of the $120 million it received to prevent foreign interference in U.S. elections.

No, Mr. President. The FBI investigation began when it was discovered that the Russians had secret discussions with your foreign policy advisor about dissemination of stolen Clinton emails.

Trump declined to implement new sanctions against Russia earlier this year, despite Congress passing a bipartisan bill giving him the power to do so.

A State Department spokesperson said at the time that the passage of the legislation was deterrent enough, and that the sanctions did not have to actually be imposed.

U.S. Cyber Command chief Adm. Michael Rogers, who also serves as director of the National Security Agency (NSA), testified before the Senate late last month that he had not received orders from Trump to stop Russian cyberattacks targeting U.S. elections.

“I need a policy decision that indicates there is specific direction to do that,” Rogers said at the time. “The president ultimately would make this decision in accordance with a recommendation from the secretary of Defense.”

Last month, special counsel Robert Mueller charged 13 Russians and three Russian entities with interfering in the 2016 presidential election.